A conventional image forming apparatus such as a laser printer includes a cover opened and closed relative to a housing of the apparatus for processing sheet jamming or for replacing a process unit with a new process unit. A locking mechanism is provided for avoiding unintentional opening of the cover when the cover is at the closed state. Upon releasing the locking mechanism, the cover is opened by a biasing force of a spring.
However, the cover is not opened when a user touches the cover or the locking mechanism may contain inherent defects in the structure utilizing the biasing force of the spring.